Read

Jump to the Code block for a combined complete example.

Create a document record

The following example demonstrates reading a document record with a JSON helper library. In Aerospike, JSON documents are handled as a Collection Data Type (CDT). A JSON object is equivalent to a map, and a JSON array is equivalent to a list.

In this example, we create the following JSON document:

employees = [{"id": "09", "name": "Nitin", "department": "Finance"},
             {"id": "10", "name": "Jonathan", "department": "Human Resources"},
             {"id": "11", "name": "Caitlin", "department": "Engineering"}]

The JSON document is added to a bin called employees which is of data type list. There are some advantages to holding an entire document in a single bin, rather than spreading out the document’s fields over multiple bins. There is less metadata overhead when namespaces contain fewer, larger bins.

Setup

Import the necessary helpers, create a client connection, and create a key.

package main

import (
  "encoding/json"
  as "github.com/aerospike/aerospike-client-go/v6"
  "log"
  "os"
  "runtime"
  "time"
)

// Policy Global policy definitions
var Policy = as.NewPolicy()
var WritePolicy = as.NewWritePolicy(0, 0)

func main() {
  host := "localhost"
  port := 3000

  // use all cpus in the system for concurrency
  runtime.GOMAXPROCS(runtime.NumCPU())

  log.SetOutput(os.Stdout)

  cp := as.NewClientPolicy()
  cp.Timeout = 3 * time.Second

  Client, err := as.NewClientWithPolicy(cp, host, port)
  if err != nil {
    panic(err)
  }

  namespace := "test"
  set := "table1"

  // clean out old record
  key, _ := as.NewKey(namespace, set, "key5")
  deleted, err := Client.Delete(WritePolicy, key)
  if deleted {
    log.Println("Deleted key:", key.Value())
  } else {
    log.Println("Did not delete key", key.Value())
  }
  if err != nil {
    log.Println("Warning - delete failed with error:", err)
  }

  documentExampleWrite(Client, key)
  log.Println("Example finished successfully.")
}

Prepare the JSON document to be sent to Aerospike.

func documentExampleWrite(client *as.Client, key *as.Key) {
    // create a slice of maps
  employeeList := []map[string]string{
    {"id": "09", "name": "Nitin", "department": "Finance"},
    {"id": "10", "name": "Jonathan", "department": "HumanResources"},
    {"id": "11", "name": "Caitlin", "department": "Engineering"},
  }

  employees := map[string]interface{}{
    "employees_list": employeeList,
  }

  // create a JSON doc of the employees
  doc, _ := json.Marshal(employees)
  log.Println("Generated JSON doc: ", string(doc))

  // unmarshal the JSON
  emps := make(map[string]interface{}, 1)
  if err := json.Unmarshal(doc, &emps); err != nil {
    panic(err)
  }
  log.Println("Restored data structure for JSON doc: ", emps)

Write

Write the document to Aerospike.

    // Store the restored structure in an Aerospike bin, then write the bin to the record.
  bin := as.NewBin("Employees", emps)
  log.Println("Attempting to insert record with key'", key.Value(), "'...")
  if err := client.PutBins(WritePolicy, key, bin); err != nil {
    panic(err)
  }
  log.Println("Insert Successful.")

Read

Read the name field from the third record in the map list.

    // read back the record from the database
  record, err := client.Get(Policy, key, bin.Name)
  if err != nil {
    panic(err)
  }

  received := record.Bins[bin.Name].(map[interface{}]interface{})
  receivedEmployees := received["employees_list"].([]interface{})
  log.Println("Read third record from database: ", received)
  log.Println(receivedEmployees[2])
}

Code block

Expand this section for a single code block to read a document record.

package main

import (
  "encoding/json"
  as "github.com/aerospike/aerospike-client-go/v6"
  "log"
  "os"
  "runtime"
  "time"
)

// Policy Global policy definitions
var Policy = as.NewPolicy()
var WritePolicy = as.NewWritePolicy(0, 0)

func main() {
  host := "localhost"
  port := 3000

  // use all cpus in the system for concurrency
  runtime.GOMAXPROCS(runtime.NumCPU())

  log.SetOutput(os.Stdout)

  cp := as.NewClientPolicy()
  cp.Timeout = 3 * time.Second

  Client, err := as.NewClientWithPolicy(cp, host, port)
  if err != nil {
    panic(err)
  }

  namespace := "test"
  set := "table1"

  // clean out old record
  key, _ := as.NewKey(namespace, set, "key5")
  deleted, err := Client.Delete(WritePolicy, key)
  if deleted {
    log.Println("Deleted key:", key.Value())
  } else {
    log.Println("Did not delete key", key.Value())
  }
  if err != nil {
    log.Println("Warning - delete failed with error:", err)
  }

  documentExampleWrite(Client, key)
  log.Println("Example finished successfully.")
}

func documentExampleWrite(client *as.Client, key *as.Key) {
    // create a slice of maps
  employeeList := []map[string]string{
    {"id": "09", "name": "Nitin", "department": "Finance"},
    {"id": "10", "name": "Jonathan", "department": "HumanResources"},
    {"id": "11", "name": "Caitlin", "department": "Engineering"},
  }

  employees := map[string]interface{}{
    "employees_list": employeeList,
  }

  // create a JSON doc of the employees
  doc, _ := json.Marshal(employees)
  log.Println("Generated JSON doc: ", string(doc))

  // unmarshal the JSON
  emps := make(map[string]interface{}, 1)
  if err := json.Unmarshal(doc, &emps); err != nil {
    panic(err)
  }
  log.Println("Restored data structure for JSON doc: ", emps)

    // Store the restored structure in an Aerospike bin, then write the bin to the record.
  bin := as.NewBin("Employees", emps)
  log.Println("Attempting to insert record with key'", key.Value(), "'...")
  if err := client.PutBins(WritePolicy, key, bin); err != nil {
    panic(err)
  }
  log.Println("Insert Successful.")

    // read back the record from the database
  record, err := client.Get(Policy, key, bin.Name)
  if err != nil {
    panic(err)
  }

  received := record.Bins[bin.Name].(map[interface{}]interface{})
  receivedEmployees := received["employees_list"].([]interface{})
  log.Println("Read third record from database: ", received)
  log.Println(receivedEmployees[2])
}